diff --git a/src/builtin.cpp b/src/builtin.cpp
index ef49ccd5e..99d5f5b52 100644
--- a/src/builtin.cpp
+++ b/src/builtin.cpp
@@ -93,7 +93,7 @@ void builtin_wperror(const wchar_t *program_name, io_streams_t &streams) {
     if (err != nullptr) {
         const wcstring werr = str2wcstring(err);
         streams.err.append(werr);
-        streams.err.push_back(L'\n');
+        streams.err.push(L'\n');
     }
 }
 
@@ -501,9 +501,7 @@ wcstring_list_t builtin_get_names() {
     return result;
 }
 
-wcstring_list_ffi_t builtin_get_names_ffi() {
-    return builtin_get_names();
-}
+wcstring_list_ffi_t builtin_get_names_ffi() { return builtin_get_names(); }
 
 /// Insert all builtin names into list.
 void builtin_get_names(completion_list_t *list) {
diff --git a/src/builtins/argparse.cpp b/src/builtins/argparse.cpp
index 195278551..04dd766ac 100644
--- a/src/builtins/argparse.cpp
+++ b/src/builtins/argparse.cpp
@@ -490,7 +490,7 @@ static int validate_arg(parser_t &parser, const argparse_cmd_opts_t &opts, optio
     int retval = exec_subshell(opt_spec->validation_command, parser, cmd_output, false);
     for (const auto &output : cmd_output) {
         streams.err.append(output);
-        streams.err.push_back(L'\n');
+        streams.err.push(L'\n');
     }
     vars.pop();
     return retval;
diff --git a/src/builtins/bind.cpp b/src/builtins/bind.cpp
index c5b31c47f..1f52c391e 100644
--- a/src/builtins/bind.cpp
+++ b/src/builtins/bind.cpp
@@ -164,7 +164,7 @@ void builtin_bind_t::key_names(bool all, io_streams_t &streams) {
     const wcstring_list_t names = input_terminfo_get_names(!all);
     for (const wcstring &name : names) {
         streams.out.append(name);
-        streams.out.append(L'\n');
+        streams.out.push(L'\n');
     }
 }
 
diff --git a/src/builtins/commandline.cpp b/src/builtins/commandline.cpp
index 5dc33a65d..cb954d64f 100644
--- a/src/builtins/commandline.cpp
+++ b/src/builtins/commandline.cpp
@@ -122,7 +122,7 @@ static void write_part(const wchar_t *begin, const wchar_t *end, int cut_at_curs
         } else {
             streams.out.append(begin, end - begin);
         }
-        streams.out.push_back(L'\n');
+        streams.out.push(L'\n');
     }
 }
 
diff --git a/src/builtins/complete.cpp b/src/builtins/complete.cpp
index 5d7edd3fd..7b237d643 100644
--- a/src/builtins/complete.cpp
+++ b/src/builtins/complete.cpp
@@ -342,7 +342,7 @@ maybe_t<int> builtin_complete(parser_t &parser, io_streams_t &streams, const wch
                 wcstring prefix(wcstring(cmd) + L": -n '" + condition_string + L"': ");
                 streams.err.append(*errors->at(i)->describe_with_prefix(
                     condition_string, prefix, parser.is_interactive(), false));
-                streams.err.push_back(L'\n');
+                streams.err.push(L'\n');
             }
             return STATUS_CMD_ERROR;
         }
@@ -356,7 +356,7 @@ maybe_t<int> builtin_complete(parser_t &parser, io_streams_t &streams, const wch
         if (maybe_t<wcstring> err_text = parse_util_detect_errors_in_argument_list(comp, prefix)) {
             streams.err.append_format(L"%ls: %ls: contains a syntax error\n", cmd, comp);
             streams.err.append(*err_text);
-            streams.err.push_back(L'\n');
+            streams.err.push(L'\n');
             return STATUS_CMD_ERROR;
         }
     }
diff --git a/src/builtins/set.cpp b/src/builtins/set.cpp
index d6d3b6e94..968638acb 100644
--- a/src/builtins/set.cpp
+++ b/src/builtins/set.cpp
@@ -546,14 +546,14 @@ static void show_scope(const wchar_t *var_name, int scope, io_streams_t &streams
     if (env_var_t::flags_for(var_name) & env_var_t::flag_read_only) {
         streams.out.append(_(L" (read-only)\n"));
     } else
-        streams.out.push_back(L'\n');
+        streams.out.push(L'\n');
 
     for (size_t i = 0; i < vals.size(); i++) {
         if (vals.size() > 100) {
             if (i == 50) {
                 // try to print a mid-line ellipsis because we are eliding lines not words
                 streams.out.append(get_ellipsis_char() > 256 ? L"\u22EF" : get_ellipsis_str());
-                streams.out.push_back(L'\n');
+                streams.out.push(L'\n');
             }
             if (i >= 50 && i < vals.size() - 50) continue;
         }
diff --git a/src/builtins/status.cpp b/src/builtins/status.cpp
index 23e1fa3aa..0c57b2b5d 100644
--- a/src/builtins/status.cpp
+++ b/src/builtins/status.cpp
@@ -454,10 +454,10 @@ maybe_t<int> builtin_status(parser_t &parser, io_streams_t &streams, const wchar
             const auto &var = parser.libdata().status_vars.command;
             if (!var.empty()) {
                 streams.out.append(var);
-                streams.out.push_back(L'\n');
+                streams.out.push(L'\n');
             } else {
                 streams.out.append(program_name);
-                streams.out.push_back(L'\n');
+                streams.out.push(L'\n');
             }
             break;
         }
@@ -465,7 +465,7 @@ maybe_t<int> builtin_status(parser_t &parser, io_streams_t &streams, const wchar
             CHECK_FOR_UNEXPECTED_STATUS_ARGS(opts.status_cmd)
             const auto &var = parser.libdata().status_vars.commandline;
             streams.out.append(var);
-            streams.out.push_back(L'\n');
+            streams.out.push(L'\n');
             break;
         }
         case STATUS_FISH_PATH: {
@@ -482,19 +482,19 @@ maybe_t<int> builtin_status(parser_t &parser, io_streams_t &streams, const wchar
                 auto real = wrealpath(path);
                 if (real && waccess(*real, F_OK)) {
                     streams.out.append(*real);
-                    streams.out.push_back(L'\n');
+                    streams.out.push(L'\n');
                 } else {
                     // realpath did not work, just append the path
                     // - maybe this was obtained via $PATH?
                     streams.out.append(path);
-                    streams.out.push_back(L'\n');
+                    streams.out.push(L'\n');
                 }
             } else {
                 // This is a relative path, it depends on where fish's parent process
                 // was when it started it and its idea of $PATH.
                 // The best we can do is to print it directly and hope it works.
                 streams.out.append(path);
-                streams.out.push_back(L'\n');
+                streams.out.push(L'\n');
             }
             break;
         }
diff --git a/src/builtins/string.cpp b/src/builtins/string.cpp
index bb993ade3..ab02c8406 100644
--- a/src/builtins/string.cpp
+++ b/src/builtins/string.cpp
@@ -775,9 +775,9 @@ static int string_join_maybe0(parser_t &parser, io_streams_t &streams, int argc,
     }
     if (nargs > 0 && !opts.quiet) {
         if (is_join0) {
-            streams.out.push_back(L'\0');
+            streams.out.push(L'\0');
         } else if (aiter.want_newline()) {
-            streams.out.push_back(L'\n');
+            streams.out.push(L'\n');
         }
     }
 
@@ -1514,7 +1514,7 @@ static int string_repeat(parser_t &parser, io_streams_t &streams, int argc, cons
         }
 
         if (!first && !opts.quiet) {
-            streams.out.append(L'\n');
+            streams.out.push(L'\n');
         }
         first = false;
 
@@ -1573,7 +1573,7 @@ static int string_repeat(parser_t &parser, io_streams_t &streams, int argc, cons
 
     // Historical behavior is to never append a newline if all strings were empty.
     if (!opts.quiet && !opts.no_newline && !all_empty && aiter.want_newline()) {
-        streams.out.append(L'\n');
+        streams.out.push(L'\n');
     }
 
     return all_empty ? STATUS_CMD_ERROR : STATUS_CMD_OK;
diff --git a/src/io.h b/src/io.h
index 8386aa997..8a410a0a1 100644
--- a/src/io.h
+++ b/src/io.h
@@ -392,8 +392,7 @@ class output_stream_t : noncopyable_t, nonmovable_t {
     bool append(const wchar_t *s) { return append(s, std::wcslen(s)); }
 
     /// Append a char.
-    bool append(wchar_t s) { return append(&s, 1); }
-    bool push_back(wchar_t c) { return append(c); }
+    bool push(wchar_t s) { return append(&s, 1); }
 
     // Append data from a narrow buffer, widening it.
     bool append_narrow_buffer(const separated_buffer_t &buffer);